Dielectric, magnetic and magneto-dielectric properties of (La, Co) co-doped BiFeO3

Abstract

BLFCO [Bi1-xLaxFe1-xCoxO3(x = 0.00, 0.01, 0.03, 0.05, 0.10)] ceramics were synthesized using sol-gel technique. The effect of Lanthanum (La) and Cobalt (Co) co-doping in BiFeO3 (BFO) on structural, electrical, magnetic and magneto-dielectric (MD) properties are systematically investigated. The phase purity and crystal structures were studied using x-ray diffraction technique. The dielectric properties [dielectric constant (epsilon) and tangent loss (tan delta)] were studied as a function of frequency and temperature for pure and co-doped BFO samples. The magnetization study reveals that the ferromagnetic (FM) properties in La and Co co-doped samples enhance with an increasing dopant concentration. The coercive field is found to increase with the doping concentration suggest a competition between the antiferromagnetic and FM ordering. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurements of these samples also confirm the change in the magnetic behaviour of BLFCO as doping concentration increases. ZFC and FC magnetization curves split at low temperature with sharp cusps suggest a spin-glass like behaviour of BLFCO. The pure and co-doped samples exhibit a MD coupling effect. Furthermore, the anomaly near the magnetic phase transition (around the Neel temperature of BFO) implies the MD coupling in BLFCO samples.